Bio-inspired, UV-blocking, water-stable and antioxidant lignin/cellulose films combining high strength, toughness and flexibility

Abstract

The use of low-cost, efficient methods to prepare thin-film materials to partially replace conventional materials in new applications is appealing. In this work, inspired by natural biological materials, we propose a strategy to prepare lignin/cellulose films with exceptional strength and flexibility by building a sacrificial network. Coordination bonds and hydrogen bonds were constructed with ultrasonic treatment and the addition of ZnCl₂ to lignin/cellulose films. The resulting films exhibited an outstanding tensile strength (up to 138.14 Mpa) and toughness (up to 12.88 MJ m⁻³). The excellent flexibility (folding resistance of 2687 times) allowed the film to be folded into complex shapes. Due to the addition of functional industrial waste lignin, the film displayed UV-blocking, water-stable, and antioxidant properties. The lignin/cellulose film is expected to be used in several new fields such as UV-blocking polymers and flexible integrated circuit boards in emerging electronics.